Warm temperatures often adversely affect blood samples that have been drawn from individuals. In poorer countries/communities, the lack of readily available refrigeration further exacerbates the situation. Not only do blood samples potentially degrade over time, but warm temperatures may alter and adversely affect the accuracy of blood test results.
A number of factors affect the accuracy of test results. Standard guidelines for blood sample handling state that plasma or serum should be separated (20-30 min) from cells as soon as possible after clot formation is complete to avoid clot-induced changes in the concentration of serum analyses. Many blood analyses deteriorate within a matter of hours in unseparated samples kept at ambient temperature. For most routine assays in a clinical laboratory, serum is the sample. The laboratory receives the specimen in the form of whole blood, and then separates the serum from the clot by centrifugation. For clinically useful and reliable test results, the interval between blood collection and serum separation must be controlled. Others have reported that some important analyses were significantly affected by temperature. For example, potassium, glucose, phosphate, creatinine, urea, ferritin, iron, lactate dehydrogenase, magnesium and calcium were not stable under storage conditions at higher temperatures. Others have reported that Serum gel or non-gel tubes might be used interchangeably for 11 analytes chilled or at 24° C., whereas some restrictions must be applied for glucose, AST, BUN, HDL, and uric acid. Still others have demonstrated that when stored at room temperature, only sodium, uric acid, bilirubin, cholesterol, triacylglycerols, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, alpha-amylase and cholinesterase remained stable after 3 days. The data collected show that all quantities examined were sufficiently stable for four days in separated serum stored at +9 degrees C. Other researchers have shown that the stability of analytes separated from serum was less at higher temperature within 20 minutes of the clot relative to the analytes at 4±1 degree ° C. 48 hours after collection.
Accordingly, people have tried to ameliorate this bad situation by many possible means.
It would be advantageous to design a test tube that would lower the temperature of the contents allowing blood samples to remain stable longer in warmer climates. This would minimize dependency on refrigeration. The thought of a design for a test tube that would improve on the design commonly used by hospitals, clinics, research, and commercial laboratories all over the world would be revolutionary. The tube design would allow drawn blood samples to withstand these warmer climes.